Sunday, April 20, 2008

It is, however, encouraging to see initiatives like Rspec which, through judicious use of higher order messages enables a much more fluent environment for writing tests:

I think that's the first time I've seen HOM used to explain something else, rather than being the
object of attention itself. So HOM is starting to be seen as simply a part of the computing landscape, at least by some. Cool.
HOM was never conceived of as an interesting thing by itself but rather as a (meta-)building block for
building more expressive computational forms. RSpec looks exactly like one of those cool things HOM
enables that I would never have come up with myself. I look forward to seeing more.

Saturday, April 19, 2008

Addendum to my article on implementing a high performance Postscript interpreter in Objective-C: not just is performance better, so is accuracy.
Despite the fact that we are optimizing the heck out of the Objective-C objects we are using, they still
give us encapsulation and polymorphism, allowing us to choose arbitrary representations. For example,
most Postscript interpreters use a fixed-size value object (polymorphic in a C-union type of way)
that constraints floating point precision to 32 bits. With Objective-C, we have no such constraints,
so EGOS floats are actually 64 bit doubles, so running the modified benchmark below in PostView doesn't just yield the result 75% faster than Preview, it also produces it with 7 orders of magnitude less error. Not that that is necessarily important in Postscript, but it is a pleasant side effect and shows the power of combining performance with abstraction.